He tried to convert the native Indians to Christianity.
Roger Williams was a seemingly ardent supporter of the cause of the native Americans and their ownership of the land and identity. He even denounced the Massachusetts Bay charter that gives permission for the confiscation of the Indians' lands by the government. But paradoxically, he himself also tried to change them, trying to persuade them to convert to Christianity and live like the Americans, leaving their identity and "Indian being" aside. This is in direct contrast to his own ideals and beliefs.
The political and religious leader Roger Williams (c. 1603-1683) is best remembered for founding the state of Rhode Island and advocating separation of church and state in Colonial America. His views on religious freedom and tolerance, coupled with his disapproval of the practice of confiscating land from Native Americans, earned him the wrath of his church and banishment from the colony. Williams and his followers settled on Narragansett Bay, where they purchased land from the Narragansett Indians and established a new colony governed by the principles of religious liberty and separation of church and state. Rhode Island became a haven for Baptists, Quakers, Jews and other religious minorities. Nearly a century after his death, Williams’ notion of a “wall of separation” between church and state inspired the founders of the United States, who incorporated it into the U.S. Constitution and Bill of Rights.
Roger Williams (1603?-1683) was a religious dissenter and the founder of Rhode Island (1636). During his fifty years in New England, Williams was a staunch advocate of religious toleration and separation of church and state. Reflecting these principles, he and his fellow Rhode Islanders framed a colony government devoted to protecting individual “liberty of conscience.” This “lively experiment” became Williams’s most tangible legacy, though he was best known in his own time as a radical Pietist and the author of polemical treatises defending his religious principles, condemning the orthodoxy of New England Puritanism, and attacking the theological underpinnings of Quakerism.
Sorry if this is to much but i hope this helps
The political and religious leader Roger Williams is best remembered for founding the state of Rhode Island and advocating separation of the church and state in Colonial American. His views on religious freedom and tolerance, coupled with his disapproval of the practice of confiscating land from Native Americans, earned him the wrath of his church and banishment from his colony. Rogers founded the first baptist church in america and edited the first dictionary of the native american languages.